Therapeutic apparatus



NOV. 9, 1937. s. BENSON 2,098,272

THERAPEUTIC APPARATUS Filed Maf0h 25, 1935 4 Sheets-Sheet l "f, 23a @j AElin-i@ Aflac/ador' Samia efas'aza Nov. 9, 1937. s, BENSQN 2,098,272

THERAPEUTI C APPARATUS Nov. 9, 1937. s. BENSON 2,098,272

THERAPEUTI C APPARATUS Filed March 25, 1935 4 SvheetS-She'et 3 ggg-fgNOV. 9, 1937. n s BENSQN 2,098,272

THERAPEUTIC APPARATUS Filed MaICh 25, 1935 4 Sheets-Sheet 4 1022 zal?93? SQP g5 .911? 62'? 5P M510@ 99 2002 ji' y L defaofx amm ezasazaPatented Nov. 9, 1937 UNITED STATES aosaz'za THERAPEUTIC APPARATUS SimonBenson, Chicago, Ill. Application March 25, v1935, Serial No. 12,863

l19 claims.

My invention relates to therapeutic apparatus. More particularly itrelates to apparatus for subjecting a member or area of a patients bodyto abatmospheric (that is, either above or below atmospheric) treatmentand to an apparatus and method for effecting an air-tight seal betweenthe member or area undergoing treatment, and the chamber or receptaclewhereby the treatment is administered. This abatmospheric treatment oruid pressure treatment (the iluid usually being air) may be by eithernegative pressure or positive pressure, or it may be by bothalternately.

The most usual purpose of this type of abatmospheric pressure treatmentis for obliterative vascular diseases and its contemplated function isto stimulate circulation through existing vascular systems including theperipheral systems and also to establish detour vascular systems aboutthe obliterations.

The chief object of my invention is the provision o f a seal which isnon-constrictive of the vascular circulation. Seals now commonly in useare of a type which tend to press against the tissues of the member orarea and thereby constrict circulation, and especially the outer orvenous circulation, thereby defeating the very purpose of the treatment.This constriction has made it necessary to interrupt negative pressuretreatment at intervals by allowing the treatment chamber pressure tocome up to atmospheric pressure or to build up to a positive pressure sovenous blood, retarded by the constriction of the seal, may be clearedand the patient be given some momentary relief from the often acute painresulting from the stifling of the venous circulation by theconstriction of the seal and this periodic interruption of the suctionto build up atmospheric or positive pressure in the treatment chamberhas been necessary even in those instances where, from the standpoint ofthe treatment itself, it would be preferable to maintain anuninterrupted suction for a long period of time.

In general, I realize my object by bringing the skin of the member orarea away from the body and against the sealing ring in sealing contacttherewith, as distinguished from bringing the sealing ring down againstthe skin and into pressure against the subcutaneous tissues. PreferablyI accomplish this by pneumatically sucking the skin outwardly against asealing ring and into sealing contact therewith. My seal is such that itmay be used, even without alteration or adjustment, for either'negativeor positive pressure in the treatment chamber or for treatment where thechamber is subjected to negative and positive pressure alternately orwhere the pressure alternates between negative or positive andatmospheric pressure. l

Another and auxiliary object of my invention is the provision of such anon-constrictive seal 5 in the two somewhat different instances of alimb, Where an encircling sealing ring may be used, and a more or lessat body area where the seal will not come along a radial face of thesealing ring, but at the lateral face thereof. The l0 gist of thedistinctions between these two instances is that with a limb, where anencircling seal may be used, the suction in the treatment chamber ismore or less balanced radiallyv of the limb; whereas in the instance ofthe flatwise apl5.

plication of the sealing ring, suction within the treatment chambertends t0 pull the chamber itself against the body, thereby creating aninward pressure which still further aggravates the objectionablevascular constriction. 20

Another object of my invention is concerned with pressure control meanswhereby the treatment chamber is subjected t'o negative and positivepressure alternately.

The foregoing, together with further objects, 25 features and advantagesof my invention are set forth in the following description of specificembodiments thereof and illustrated in the accompanying drawings,wherein: f

Fig. 1 is a diagrammatic view in elevation of 30 apparatus forsubjecting an arm to uid pressure in a chamber;

Fig. 2 is a plan view of the chamber and sealing cuff;

Fig. 3 is a vertical sectional view of the cufl` 35 and cover of thechamber, taken along the line 3-3 of Fig. 2;

Fig. 4 is a detail view of the cuff, taken along the line 4 4 of Fig. 2;

Fig. 5'is a longitudinal vertical section of a 40 treatment chamber ofthe type adapted to receive a leg, and incorporating another andpreferred form of seal;

Fig. 6 is an enlarged vertical section through the sealing ring of Fig.5; 45

Fig. 7 shows in radial section a modified form of sealing ring;

Fig. 8 shows in radial section still another form of sealing ring;

Fig. 9 is a transverse detail section of the seal 50 of the form of Fig.8, taken on the line 9-9 of Fig. 8;

Fig. l0 shows still another modified form of seal in radialseCtion;

Fig. 11 shows in vertical section a treatment 55 chamber and sealingring of the type adapted for application more or less atwise to a bodyarea;

Fig. 12 is a side elevation of the pressure generating and controllingapparatus, showing in connection therewith the chamber of Fig. 5;

Fig. 13 is ay vertical transverse section of the pulley wheels, takenon'the line |3|3 of Fig. `12;

Fig. 14 is a radial section, taken on the line |4|4 of Fig. 12 throughthe Vrim of the cam wheel, showing atypical cam block;

Fig. 15 is a perspective View of a typical cam block for thecam Wheel; l

Fig. 16 is a development of the built-up cammed periphery of the camwheel, and 4 Fig. 17 is a horizontal section of the regulating valves,taken on the line |`|-|'l of Fig. 12.

This application constitutes a continuation in part of my applicationSerial No. 515,350, led February 12, 1931, on Apparatus for sealing.

In the form ofFigs. 1 to 4, inclusive, I have shown a verticallydisposed cylindrical chamber 2| large enough'to contain comfortably amans arm. An air-tight cover 22 is secured to the top.r

of the chamber in any readily removable fashion. The cover-has an inlet23 and an outlet 23a, each provided with a stopcock. The cover has acentral opening conforming to the shape of the portion of the bodymember to be sealed. A sealing ring or cui 24 is 'fitted into thisopening and securely attached to the cover. The cuff may be made ofmetal,` glass, hard rubber, or composition materials. IAs shown in Fig.4, the vertical surface ofthe culi is slightly concave and thehorizontal section follows the cross-section of the body memberto besealed.

It is essential 'that the portion of the member upon which the seal isto be made when the member is in thechamber be in close proximity to theinside wall ej the cuff, but it must not t so snuglyfthat lthecirculation of the blood is in any manner .constrained or impaired.Since the size and shape of mens, womens and childrens limbs varygreatly, andsince on some occasions it will be desirable' to seal` theentire leg or arm of vthe'patient, rand on others just a portion of thememberfit is necessary for doctors and others giving treatments, ashereinafter described,l to have available a supply of cuffs of diierentsizes and shapes. However, cuis fashioned from hard rubberor acomposition material and provided with slots to receive sections toenlarge the cuff .have eliminated somewhat the necessity of mainorsealing ring, with an annular recess or cham- A'ber 25 between thecasings or walls.

AThe outer casing 26 is rigid and restsupon and is secured to the top ofthe cover. The elliptical inner wall or casing is comprised of threeparts, as bestshown inFilg. 4, the top section 2'! being a coninwardlyof the upper and lower sections, comtinuation ofthe outer casing 26 bentover in the nature of a bead, thus forming a closure for the recess 25between the walls. The lower section 28 of the inner wall is tted intothe opening of the cover and is `secured to the inner side of the coverand extends somewhat above it. A section of foraminous materialZS-preferably ne mesh wire screening-extends between and .sealed bodymember. The various parts may be of metal secured together in aleak-proof manner, for example by soldering.

As shown diagrammatically in Fig. 1, the tubing 30 connects the airrecess 25 of the cui with a vacuum pump 3| and a manometer 32. The

vacuum pump 3| is employed to reduce the pressure inthe air recess 25.The chamber 2| is here shown as containing water as the fluid medium. Aseal is effected between the chamber and the arm by sucking the skin ofthe arm adjacent the cuff 24 against the concave inner wall of the cui.'This sucking is accomplished by reducing the pressure in the air recess25 by operating the vacuum pump 3|. 'I'he skin adjacent the entire innerwall is thus drawn tightly against said wall and forms an effectiveseal. In case the skin should be drawn away from the cui in any manner,the break in the seal would be immediately' reected in the manometer 32.The advantage of my apparatus lies in the fact that an air-tight seal issecured without in any I shall next describe the apparatus forsubjecting the chamber 2| to negative or positive pressure. Tubing 34connects a graduate 33 with the chamber past a stop cock 35. Anothermanometer 36 and another pump 31 gcapable of producing both negative andpositive pressure) are separately connected to the graduate 33. Inoperation, the patients forearm-or, in apparatus of' different size andshape, the patients leg-is placed within the chamber 2| and the cuff 24.The arm and cuff are then sealed in the manner described and the chamberand 'tubing to the inlet to the graduate illled with water (if a liquidmedium is to be employed) through the inlet 23. the stop cock 35 beingopen while the chamber and tubing are being iilled.

When the apparatus is used for therapeutic treatment, the pump 31 isoperated to intermittently reduce and increase the pressure within thechamber. 'Ihis may be done, for example, by reversing the motor of thepump, or by connecting the conduit to the chamber alternately to thenegative and pressure sides of the pump, de-

pending of course upon the type of pump employed.

In Figs. 5 and 6, I have shown another and preferred form of sealingapparatus in conjunction with another form of chamber, this chamberbeing shown as adapted for the reception of a leg. Here the chamber 4|,which is glass-walled for ready observation of the leg, is of generallycylindrical shape except that it has an upper enlargement 4|' for theaccommodation of the toes and ttings. A pressure inlet fitting 42, whichpreferably includes a pressure gage, is inserted into the chamber at thetop of the enlargement 4| by means of a rubber stopper, for example, andis connected with the chamber end of a treatment pressure hose 43leading from a regulated source of pressure, which as hereinafterexplained may be either negative pressure or positive pressure, or bothalternately. The vchamber is preferably provided also with a thermometer44 and an electric heating unit 45, it being desirable in many instancesto conduct a treatment under controlled elevated temperatures.

The open end of the glass chamber 4| through which the leg is inserted,is provided with a sealing cuff 46 of rubber or other exible but notlimp material. The cuff may be of frusta-conical shape with its enlargedend embracing the beaded end ofthe chamber 4| vand secured thereto by aclamping ring 41. The smaller or outer end of the cuff 46 forms asealing ring 48. To prevent collapsing of the cuff under internalsuction, while permitting considerable flexibility, I prefer toincorporate longitudinal stays 49 at radially spaced intervals, whichstays may be molded into the rubber of the cuff. The sealing ring 48 maybe of rubber molded integrally with the body of the cui. The rubber ofthe ring, 48 is preferably of about the exibility of the tread of anautomobile tire or slightly more resilient andexible. To be precise, thering should be resilientenough easily to adapt itself to varying ovalshapes, out of its normal round, so that it will adapt itself to thecontour of a patients legs, and still not be so limp that it will buckleand thereby ensmall its circumference, lfor the latter would result in aconstriction of the limb.

The ring 48 has an inner skin-engaging face 50 which opens into asealing recess or chamber '5| by a slot 52 through the sealing face,leaving annular corners 53. A nipple 54 molded into the outer wall ofthe sealing ring 48 receives the end of a sealing suction hose 55 from asuction source which will later be described. The cui 46 is chosen froman available assortment of sizes so that the inside diameter of thesealing ring 48 is approximately that of the region of the leg to betreated at some convenient point above the knee. Advantage can be takenof the normal taper of the thigh to avoid the necessity of exact sizefor the sealing ring, the leg being pushed in until the tapering thighsubstantially fits the sealing ring which, as previously mentioned, iseasily deformed to accommodate itself to the oval cross-section of thethigh. When the recess 5l is subjected to the sealing suction throughthe hose 55, the skin is drawn into the recess, making sealing contactall around the thigh at two longitudinally spaced circles dened by thesalient corners 53 over which the skin is thus drawn. But to avoiddrawing the skin so far into the recess 5i that the skin will becomeunduly stretched over the corners 53 and become painful, I provide askin-supporting foraminous wall 55 of woven wire or perforated sheetstock, molded into the rubber of the sealing ring 48, as shown in Fig.6. This limits the in-drawing of the skin, but littl-e step-down beingrequired to render the salient corners 53 effective for sealing contact.

As far as the sealing itself is concerned, this may be accomplished bythe modification shown in Fig. 7, where the sealing ring 48a has anarrow slot 52a. in its skin-engaging face 58a leading to the suctionrecess Ella, but no supporting wall is used across the recess. The skinwill be sucked into effective seal with the closely spaced salientcorners 53a., but, as compared with the form of Fig. 6, this has twoobjections. One is that the skin will be drawn out into the slot to forma narrow but high ridge, which will prove painful to the patient andleave an objectionable ring for some time. The other objection is thatthe total area of the skin subjected tothe sealing suction is much lessand, therefore, the skin can be torn away from sealing contact with thesealing ring by lesser force than is required in Fig. 6, for example,where the area of skin subjected to suction is considerably greater.

In Figs. 8 and 9, I have shown a further modication of sealing ring 4817where the skin-engaging faces 50i)I may be formed by a pair of metalrings each of L-shaped radial section, although the same principle maybe worked out all in molded rubber. Here the slot 52h dening the salientcorners 53h does not open directly into the sealing recess 5Ib, nor isthere a perforated skin-supporting wall. Instead, the skin-supportingWall 56h is imperforate, but spaced from the back side of theskin-engaging face 50h by fluted edges 54h. Thus, the sealing suction towhich the recess 5Ib is subjected finds its way to the skin around thelateral edges of the Wall 56h and sidewise into the slot 52h.

In Fig. 10 I have shown a still further modification of the sealingring. Here the sealing ring 48e is built up from thin and ratherflexible sheet metal and the skin-engaging face 50c is flush with acentral perforated area 54e Without employing outstanding annularcorners such as 53. This form of seal is not so satisfactory inoperation because, lacking the annular sealing ridge 53, a pull on theskin away from the sealing face 50c can easily overcome the small forceof the suction on the area of one or two of the holes of the perforatedarea, freeing them independently of the others. Then, another two orthree can be` released independently of the others, and so on, until theentire seal is broken by increments. Also, as the skin is drawn awayfrom more and more holes, the atmospheric leakage into the sealingrecess 5Ic reduces the suction therein and further contributes to theready collapse of the entire seal.

When the treatment chamber 4l is subjected to negative pressure, it willtend to suck the leg in farther into the treatment chamber by a forcerepresenting the pressure times the area encompassed by the sealing ring4B. Pulling the leg farther into the treatment chamber would have theobjections of longitudinally stretching the skin of the contained leg(inasmuch as the seal 48 will not permit the slipping of the skin) andof the tapered thigh when moved farther in, bringing a region of thethigh of larger diameter into the sealing ring to the extent allowed bythe sliding of the skin upon the subcutaneous tissues, therebyconstricting circulation. To prevent such inward movement of the leg Iprovide a footrest R within the treatment chamber which footrest may beadjusted by external manipulation of a screw which is threaded through abushing in the end wall of a chamber, as showin in Fig. 5. Or, thetreatment chamber and the body may each be secured to the bed ortreatment table. I

When the treatment chamber is subjected to positive pressure, there is acorresponding tendency to push the leg out. This may be remedied by thelatter suggested arrangement or by suitably harnessing the treatmentchamber to a waist belt or shoulder yoke.

In Fig. 11 I have shown a modified arrangement of seal adapted to atreatment chamber which is applied more or less flatwise against a bodyarea in those instances where the part to be treated is not in thenature of a limb which can be encircled by the sealing ring. In otherwords, Fig. 11 shows an arrangement where the sealing ring faces thebody sidewise with its lateral face against the body, as distinguishedfrom the forms previously described, where the seal may be of Fig. 11 isshown in an exemplary application to a breast. It is provided with apressure inlet yfitting 42d, and associated pressure gage, connectedwith the treatment pressure hose 43. It

also has a thermometer 44d and electric heating element 45d. The sealingring 48d is connected with the open end of the cup by a flexible collarwhich, by analogy, I shall call a cuff 46d which is held against thechamber by a clamping ring 41d. The skin-engaging surface 50d of thesealing ring 48d is on the lateral side rather than facing radiallyinwardly, but, as in the form of Fig. 6, it includes a central slot 52ddefining concentric circular salient corners 53d and leading through aperforated skin-supporting Wall 54d to the annular suction recess 5|d.

Whereas in the encircling form of sealing ring the vring is preferablyyieldable out of its round configuration, to accommodate itself to thecontour of the limb, in the tangential application of Fig. 11 thesealing ring must be yieldable out of a piane, because there are fewplaces on the body where a planar sealing ring would effect a closeenough t with the body area to provide a satisfactory seal. Theflexibility of the rubber of which the sealing ring 48d is formed,permits it to be moved out of a plane to accommodate itself to thecontour of the body. For holding the skinengaging face 50d of thesealing ring in this nonplanar body-conforming position I provide aplurality of, say, six arcuately spaced sockets 51 molded into the ring48d. Each of the sockets 51 embraces the balled end of a threadedpositioning rod 58. The rods 58 pass through ears 60 outstanding atcorresponding arcuate intervals from the clamping ring 41d. By thumbnuts 59engaging the upper and lower faces of each ear 60, each rod 58may be positioned vertically to hold the sealing ring at that region atthe desired height relative to the treatment chamber, to effect theconformation of the sealing ring to the body. The holes in the ears 60'through which the rods 58 pass, are preferablyradially elongated becausethe radius of the rod from the vertical center line of the treatmentchamber will vary at diierent elevations of the sealing ring.

In Fig. 11, it will be understood that the patient is lying on the backupon a treatment bed or table. For supporting the treatment chamber Iprovide a standard 62 which may rest upon the floor and carries avertically adjustable U-shaped bracket GI, the arms of which areconnected to diametrically opposite sides of the clamping ring 41d, asby trunnions.

The supporting standard not only relieves the patient of the weight ofthe treatment chamber, but, also, through the sealing ring positioningrods 58, definitely holds the sealing ring at a fixed elevation so thatthe skin is sucked up against the sealing ring rather than the sealingring being sucked down against the skin and thereby constricting thecirculation into the region being treated. The sealing ring so firmlyengages the skin bounding the area being treated that, even though thetreatment chamber be subjected to considerable negative pressure, thetendency of thattreatment suction to pull the exposed area into thechamber is successfully resisted. The sealing ring 48d, while flexible,is sufficiently rigid to withstand such buckling as would ensmall itsperimeter, and thus the sealing ring itself can not be drawn radiallyinwardly or upwardly by negative pressure in the treatment chamber.

I shall next explain the apparatus for supplying controlled pressure tothe treatment chamber and the sealing rings of the forms shown in Figs.5 to 11, inclusive.

The specic type of treatment suction control apparatus which I have hereshown somewhat schematically in Figs. 12 to 17, inclusive, has beenselected because it affords a wide range of flexibility. The treatmentsuction may be kept at a constant negative pressure or at a constantpositive pressure, or it may be periodically varied betweenpredetermined degrees of pressure, either al1 negative pressure or allpostiive pressure or alternating between positive and negativepressures, and the transitions between various degrees of pressure maybe accomplished either abruptly or very gradually, and the time periodof the cycle may be varied as well as the proportion of time allotted toeach predetermined degree of pressure. In short, the pressure control isarranged to provide the desired degree of pressure in the treatmentchamber for each moment throughout a predetermined cycle.

Such pressure control apparatus as here illustrated comprises (Fig. 12)an electric motor 65, a suction or negative pressure pump 66N, and apositive pressure pump BGP conveniently arranged upon a common base 68.Through a manually shiftable clutch 69 the motor drives a worm 10 whichengages a Worm wheel 1| on a transverse shaft 12. The worm wheel shaft12 carries a lower stepped pulley 13 (Fig. 13) which drives an upperstepped pulley 14 on an upper pulley shaft 15, also journaled in apulley frame 16, through a belt 11. The upper pulley shaft 15 alsocarries a cam wheel 18 which operates the pressure control valves as thecam Wheel revolves. The cam wheel 18 has a peripheral rim 18 (Fig.I 14)in the outer face of which is a centrally arranged annular slot for thereception of the securing flanges of the various cam blocks B (Fig. 15).A

A,yokeiike bracket 8l, which may be a fixed extension of the pulleyframe 16, supports on one side of the cam wheel (Fig. 17) a positivepressure control valve indicated generally .as 82P and on the other sidea negative pressure control indicated generally as valve 82N.

I shall rst describe in detail the positive pressure control valve 82Pfor the treatment chamber. A positive pressure control arm BSP ispivoted at one end at 84P on the xed bracket 8|, while thel other endcarries a roller 85P which engages the adiacent lateral cam faces ofsuccessive cam blocks B arranged about the periphery of the cam wheelrim 19. Through an adjustable cap screw BBP the arm BSP engages theinner spring cup 81P which embraces one end of a spiral regulatingspring 88P, the other end of which is embraced by an outer spring cup89P. The spring may be encased by a telescoping cylindrical shell SOP.

The outer spring cup 891? is mounted on the end of a protruding valvestem SIP which is slidably mounted in and extends through the valve body92P. The valve stem carries a pair of `spaced valve heads 93Pcooperating with valve seats 94P to provide a substantially balancedvalve. The valve controls the flow of air from the pump side passage 95P(which is connected by a pipe BBP to the discharge side of the positivepressure pump SSP) to the chamber side passage 91P of the valve body(which is connected through a pipe 98P to a T fitting 99 which, in turn,is connected to the hose 43 leading to the treatment chamber).

The valve stem SIP is normally urged to its Aclosed position by a lightbiasing spring |001?. A

diaphragm IMP is fixed across the open side oi.' a cupped diaphragmhousing |02P defining a diaphragm chamber |03? subject to the pressureof the treatment chamber by a small tube |04P leading from the chamber|03P to the chamber side passage STP.

. The operation of the positive pressure control valve 82P, whosestructure has just been described, is as follows: If the cam blocks B onthe cam wheel have been so arranged as to call for positive pressure inthe treatment chamber at spine point in the revolution of the cam wheel(that is, at some period during the cycle of operation), the cam faceofa suitably conformed cam block B will engage the roller 85P, camming itupwardly (Fig. 17) to swing it about the pivot 84P and thereby press thespring cup 8`|P upwardly. The diaphragm chamber |03P being at or underatmospheric pressure, no resistance is .offered to the upward movementof the valve stem SIP, save the easily overcome biasing spring |P.Accordingly, the valve heads 93P open, permitting air under positivepressure to pass from the pump side passage 95P (which is supplied inexcess of maximum requirements by the positive pressure pump 66P) to thechamber side passage 91P and thence through the hose 43 to the treatmentchamber. As pressure builds up in the treatment chamber it willcorrespondingly build up pressure inthe diaphragm chamber |03? until thedownward pressure on the diaphragm overbalances the pressure of theregulating spring 88P, corresponding to the compression as xed by thepositionof the arm 83P, and upon the occurrence of such overbalancingthe valve will be fully closed. Whenever the positive pressure in thesuction chamber falls below that determined by the position of the arm83P, the spring 88P will overbalance the reduced pressure in thediaphragm chamber |03P and reopen the-va1ve until the pressure has againreached the predetermined degree.

When the cam blocks B call for a reduction in positive pressure, after apositive pressure has been built up, the arm 83P will swing downwardlyleaving thevalve closed. Ordinarily this would leave trapped in thetreatment chamber 4| the maximum positive pressure which was built upand the treatment chamber positive pressure would not bereduced, ascalled for by the cams. To avoid such a situation I provide a reliefvent valve |05 in the form of an adjustable needle valve which permits asmall but constant bleeding of the chamber pressure line through thevent |06. This gives a fairly prompt relief for any positive pressuretrapped in the treatment chamber after the cam wheel has required alesser positive pressure. The relief needle valve |05 is set for such anadjustment that pressure will -be-relieved in the treatment chamber atthe maximum rate at which it will be desired to have the pressure drop.On the other hand, the relief port will not be so great as to throw anunnecessary burden on the positive pressure pump or substantially impedethe rapid building up of desired positive pressures within the treatmentchamber.

When the treatment chamber is subject to negative pressure, thecorresponding negative pressure will also obtain in the diaphragmchamber |03P, tending to liftthe diaphragm I0|P.

It is therefore important that the upper end of the valve stem SIPmerely abut the diaphragm |0|P instead of being secured thereto, forotherwise,subjecting the treatment chamber t0 suction` pressure. wouldopen the valve 82P and destroy the negative pressure.

I might explain, to avoid any confusion. that in referring to Fig. 17,where I have used the terms up and down in connection with the operationof the valve parts, I am using the terms only in reference to the sheet;the figure is a horizontal plan section and the parts work in thehorizontal plane. l

The negative pressure control valve 82N, as will be seen from Fig. 17,is substantially similar in construction and operation to the positivepressure control valve 82P just described, save that the'roller 85Ncontacts the opposite face of the several cam blocks B and the diaphragmchamber |03N is in reverse arrangement so that when it is subject tonegative pressure the diaphragm |0|N tends to close the valve.

The pump side passage 95N communicates with the pipe 96N leading to theintake of the negativepressure pump 66N.

The operation of the negative control valve is as follows: When the camblocks B on the cam wheel engage the roller 85N to swing the control arm83N downwardly tending to compress the spring 88N to open the valve, thediaphragm |0|N yields, permitting the valve to open. Air is thus drawnfrom the treatment chamber through the hose 43 and pipe 98N past thevalve and through the pipe 96N to the suction pump 66N. When thenegative pressure built up in the treatment chamber, and communicated tothe diaphragm chamber |03N, is sufficient to overbalance the pressure ofthe spring 88N as compressed by the position of the arm 83N, the valvewill close. The constant relief afforded by the valve |05 insures thatwhen the cam wheel. calls for a decreased amount of negative suction inthe chamber, the high negative suction will not be permanently trappedin the treatment chamber.

YBefore describing in detaii the arrangement of the cam' blocks B on thecam wheel, I shall explain the regulation of the sealing suctionadmitted to the sealing ring. The sealing suction regulating valve,indicated generally at 82S, is here shown as of substantially the sameconstruction as the negative pressure regulating valve 82N except thatthe regulating spring 08S is subjected to a predetermined pressure orset-I ting by a suitably indexed hand screw 83S rather than by acam-operated arm or'lever. The pump vside passage 95S of the valvecommunicates with the negative pressure line 96N from the pump 66N whilethe sealing side passage 91S is connected to the sealing suction hose 55leading to the sealing ring 48.

In the operation of the sealing ring it is'often vdesirable to employ arelatively high sealing suction initially to pull the skin into sealingcontact with the ring and then drop the sealing suction to a lowersuction merely suilicient tomaintain the seal once it has' beenestablished. These predetermined sealing suctions may be secured by themanual adjusting screw 83S and aided by 'suitable indicia which may beplaced on the hand treatment chamber. And similarly,.this relief valveinsures that the sealing suction is reduced to atmospheric pressure whenthe valve 82S is adjusted to cut oi the sealing suction.

Referring again to the cam blocks B disposed in series about theperiphery of the cam wheel 18, a typical cam block B is shown in Figs.14 and 15. The top and bottom surfaces are arcuately conformed about aradius from the axis of the cam wheel 'I8 so that when the blocks areset on the cam wheel their undersides mate the peripheral face of therim "I9 of the cam wheel. Each block B carries a depending flange III),which extends the length of the block at one lateral edge thereof. Theange I I0 nts into the annular slot 80 on the peripheral face of the camwheel 'I8 and is secured to the cam Wheel by a locking pin III whichextends through a hole II2 in the rim 'I9 and through a registering holeI I3 in the flange I I0. The locking pin III may have a protrudingknurled head and av threaded portionl lwhich is screwed into the tappedend of the hole II2 for securing the locking pin. One face, II4, of eachcam block B constitutes a cam face for engagement with one of therollers 85P-85N. Each cam block, it will be seen, is reversible wherebyit may be set into the slot 8U so that its cam face II4 will bepresented to whichever of the rollers BSP- 85N `is required by the cycleto be established. The

transverse Idistance between thecam face II4 and the securing ange IIUdetermines the lateral displacement of the roller by the cam block. Theface I I4 may be parallel with the ange H0, in which case thevregulating valve will be held at a constant pressure during the arcuatetravel of the block along the roller, or the face II4 may be at aninclination to the flange H0, in which case, when the given .cam blockpasses the roller, the roller ywill be swung transversely outwardly orinwardly as the case may be.

For convenience in building up a series of cam blocks B to give thedesired cammed contour to the cam Wheel, the cam blocks, as to theirarcuate lengths, are built up in multiples of 10 degrees. The peripheralface of the rim 19 may carry such radial indicia H5 as is shown in thedevelopment of the periphery of the cam wheel `which constitutes` Fig.16. When the blocks are worked out on the basis of lO-degree multiples,locking pin holes H2 occur every 10 degrees, thus making a totalof 36holes H2 about the lateral face of the cam wheel rim 19. It is onlynecessary,h'oWever, that a single locking pin be used for each cam blockB although it is a convenience that the ang'e IIU of each cam block B beprovided with a hole I I2 for each 10 degrees of arcuate lengthof thecam block.

I contemplate that in a hospital or clinical installation ofthetreatment apparatus using the control here shown, a large variety of camblocks B will be available. The several cam blocks Will vary in arcuatelength in the lateral displacement of the cam faceI I4 from the securingflange Illl and in the inclination of the face II4 to the flange IIU.Certain multiples for the transverse width of the cam block may beadhered to and indicated by indexed lines I I6 engraved on theperipheral face of the rim 29, as shown in Fig. 16. With the indicia II5reading in terms of degrees and the transverse indicia II 6 reading interms of pressure, the peripheral face of the cam wheel rim 'I9 forms,in effect, the coordinated background or field for a pressure linewhich, instead of being drawn'as a pencil line, is actually physif callybuilt up by the faces I I4 of the cam blocks B.

lIn Fig. 16, going upwardly from the ,slot represents positive pressure,while going downwardly from the slot 80 represents negative pres,-

sure. where the cam prole has been built up to show the flexibility ofthe control rather than to show any therapeutically preferable cycle-therst cam block BI has a cam face which is inclined from initial zeroposition to a negative pressure position. Thenext cam B2 continues theinclination up to a predetermined level, which is sustained by thefollowing three cam blocks B3, B4 and B5. As the cam Wheel is revolvedin the direction represented by the arrow in Fig. 16, the positivepressure roller P will ride against the back face of the cam blocks,retaining the positive pressure control valve 82P in its zero or closedposition. The inclined cam faces of the blocks BI and B2, however, willgradually dis-1 place the roller 85N, causing corresponding nega.-

tive pressure to be built up and maintained in the treatment chamber.After theV negative pressure in the treatment chamber has beenmaintained at a constant amount during the passage of the cam blocks B3,B4 and B5, the roller 85N next encounters another outwardly inclined camblock B6 which increases the negative suction in the treatment chamberand this higher negative pressure is maintained by the ensuing 'blocksBl and B8. In the instance of the latter two blocks, it will be seenthat when a constant negative pressure is to be maintained for 50degrees of revolution of the cam wheel, this may be effected by usingone 20degree cam block and one {l0-degree cam block, both, of course, ofwidth corresponding to the desired pressure to be maintained.

Still following the example of Fig. .16, the roller 85N would next bepassed by the cam block B9 which is inclined slightly to reduce thedegree of negative suction in the treatment chamber. It is at this pointthat the bleeder or relief valve I05 functions to avoidtrapping in thetreatment chamber the high suction built up by the cams B6, B1, B8.Following the inclined cam B9, the slightly reduced negative pressure ismaintained for another 40 degrees by the cam blocks BIO and BI I. Thenthe inclined cam block BIZ reduces the negative pressure to zero. Itwill be In the exemplary instance of Fig. 16-

observed that by the great inclination of the cam .BSP and 85N to standin zero pressure position.

The next cam BI4 is arranged so that its inclined cam face is on theopposite side of the ange I I0. The cam block BI4 thus engages the.positive 'pressure regulating .roller 85P and gradually laterallydisplaces it to provide a constantly increasing positive pressure in thetreatment chamber. This positive pressure is built up through y20degrees and then maintained through 30 degrees by the cam block BIS andthen returned through 20 degrees to zero pressure by the cam block BI 6.'I'here is a short IO-degree dwell at zero pressure or' atmosphericpressure by the cam block BIT. This completes the cycle which will beimmediately repeated by the continued rotation of the cam wheel. It willbe observed that it is physically impossible, with cam blocks ofv thisdesign, to provide an anomalous situation supplying both negative andpositive pressure simultaneously toA the treatment chamber.

In this manner each revolution of the cam Wheel 18 provides a cycle ofoperation for the treatment chamber, as regards the pressure therein.But the time period of that cycle is determined by the combination ofpulleys employed in the stepped pulleys 13 and 14, which can be soproportioned as to give any desired speed to the cam wheel. In instancesWhere, for example, a predetermined suction pressure is to bemaintainedin the treatment chamber for a relatively long period of time,the cam wheel may be rotated to a position corresponding to the desirednegative pressure to be maintained,` and the clutch 69 may then bedisengaged, leaving the cam wheel stationary and maintaining the desirednegative suction in the treatment chamber until the clutch is againengaged.

It will be understood that the suction and pressure pumps 66N and 66Pare of a blower type which inherently provide for their own relief whenthey have built up their maximum suction or pressure. Where other-typesof pumps are employed it may be necessary to use, as a source of suctionand pressure for the regulating valves, a pressure reservoir tank and asuction reservoir tank suitably maintained by pressure controlled pumps.

While I have shown and described these specic embodiments of myinvention, I contemplate that many changes lmay be made therein withoutdeparting from the scope or spirit of my invention.

I claim:

1. A device of the character set forth compris ing a chamber, a coverfor said chamber provided with an opening the size and shape of a humanarm, a concave annular wall tting into said opening, a section offoraminous material forming a part of said concave wall, an outerannular wall surrounding said inner wall forming a recess intermediatethe walls, and means for reducing the pressure within said recess.

2. The combination of a fluid pressure receptacle having an opening bymeans of which a part of a living body is exposed to the interior of thereceptacle, the mounting and arrangement of the receptacle relative tothe body partfbeing such that the receptacle is withheld fromcirculation-restricting movement against the body part by the pressurewithin the receptacle, a relatively rigid recessed member framing saidopening', the recessed member having a pneumatically permeable sideccrnmunicating with therecess constructed and arranged for placementproximately facing the skin bounding the area of the body part exposedto the interior of the receptacle, and means for partiallyevacuating'the recess to suck the skin into fluid-tight sealing contactwith the permeable side and away from the adjacent portion of the bodypart, whereby the recessed member is non-constrictive of vascularcirculation.

3. The combination of a suction receptacle having an opening by means ofWhich a part of a living body is exposed to the interior of thereceptacle, the mounting and arrangement of the receptacle relative tothe body part being such that the receptacle is withheld fromcirculation-restricting movement against the body part, means forsubjecting the interior of thereceptacletovaryingabatmosphericfluidpressures,

a recessed member, of greaterrigidity than the tissue of the bodymember, framing the opening and having a pneumatically permeable sidecommunicating with the recess constructed and arranged for placementproximately facing the skin bounding the body part area exposed to theinterior of the receptacle, and means for partially evacuating therecess to such the skin into fluidl tight sealing contact with thepermeable side and away from the adjacent portion of the body partwhereby the recessed member is non-constrictive of vascular circulationwithin the body part, the degree of suction in the recess beingdifferent from the degree of pressure in the receptacle.

4. A means for effecting a gas-tight seal between the wall of an openinginto a receptacle and the skin of a portion of a living body tissueexposed by means of the opening to the interior of the receptacle, saidmeans comprising a relatively rigid recessed member framing saidopening, said member having aside which may be brought into closeproximity to the skin bounding the area exposed to the interior of thereceptacle, the side comprising a. pair of spaced apart annular salientsurfaces for effecting primary seals with the skin and a perforatedskin-supporting member extending across the space between and oilsetfrom the salient surfaces, and means for partially evacuating the recessin said member to cause the proximate tissue to be sucked against theopen side thereof and away from the body tissue, whereby the recessedmember is non-constrictive of vascular circulation within the bodytissue.

5. The combination with va receptacle having an opening through which anextremity of a living' body extends into the interior of the receptaclefor subjection to the pressure within the receptacle, and means forsubjecting the interior of the receptacle toabatmospheric pressure-ofmeans for effecting a duid-tight seal between the receptacle and thebody extremity said means comprising an annular sealing member, ofgreater rigidity than the tissues of the extremity, encircling theextremity and sealed to the receptacle and having a recess, apneumatically permeable wall for the sealing member communicating withthe recess and arranged proximately to `face the skin of the extremity,and means for subjecting the recess to suction to suck the skin, in agenerally radial direction, away from the adjacent portion of the bodyextremity, into, and to maintain it in, sealing contact with the sealingmember.

l 6. The combination with a receptacle having an opening through whichan extremity of a living body extends into the interior of thereceptacle'ffor subjection to the pressure within the receptacle, andmeans for subjecting the interior of the receptacle to varyingabatmospheric pressures, of means for eiecting a duid-tight seal betweenthe receptacle and the body extremity, said means comprising arelatively rigid annular sealing member encircling the extremity andsealed to the receptacle and having a pneumatically permeable sideproximately facing the skin of the extremity, a recess in the sealingmember communicating with vthe permeable side and means for subjectingthe recess to suction to suck the skin, more or less radially away fromthe body extremity, into, and to maintain it in, sealing contact withthe sealing member, the degree of suction in the recess being differentfrom the degree of abatmospheric pressure presently within thereceptacle.

'7. The combination of a receptacle, means for lsubjecting its interiorto abatmospheric pressure,

an opening in the receptacle through which a limb of Aa human body maypass for subjecting the limb to the interior pressure, a cuff sealed tothe rreceptacle and encircling the limb at the margin of its exposure tothe interior suction, and means for sucking the skin of the limb awayfrom the limb and into sealing contact with the cuff, whereby the cuiris non-constrictive of vascular circulation within the leg.

8. A means for effecting a gas-tight seal between the wall of an openinginto a primary treat- 'v ment receptacle and a. portion of living tissueexposed to the interior of the receptacle through the opening thereof,said means comprising a relatively rigid secondary recessed sealingcham- 4 ber member framing the opening into the receptacleithrough whichthe tissue is exposed, said member havingan open side which may be .theportion to the-interior of a treatment cham- Cil ber by an openingthereinto, subjecting the chamber to abatmospheric treatment pressure,and pulling the proximate surface of said body portion into sealingcontact with the margin of the opening by subjecting such surface tonegative pressure different from the abatmospheric pressure in thetreatment chamber.

10. 'I'he combination of a receptacle constituting a pneumatic treatmentchamber subject to abatmospheric treatment pressure and having anopening for exposing a portion of a body member to the treatmentchamber, a sealing ring around the opening sealed to the receptacle andcomprising a lateral skin-engaging face, having a pair of spaced annularimperforate sealing margins, directed more or less flatwise against theannular area of skin bounding the portion exposed to the chamber throughthe opening, and passage means subjecting to suction portions of theskin-engaging face intermediate the spaced sealing margins for holdingthe skin in sealing engagement with thesealing ring.

11. The combination of a receptacle constituting a treatment chambersubject to abatmospheric pressure and having an opening for exposing aportion of a body member to the treatment chainber, a sealing ringhaving a. skin-engaging face for application more or less flatwise tothe body portion, a flexible sleeve sealing the ring to the receptacle,and a pneumatically permeable annular slot in the skin-engaging face ofthe sealing ring, and passage means for subjecting the slot to suctionfor holding the proximate skin in 'sealing contact with the sealingring.

12. The combination of a receptacle constituting a treatment chambersubject to abatmospheric pressure and having an opening for exposing aportion of a body member to the treatment chamber, a sealing ring havinga skin-engaging face for application more or less flatwise to the bodyportion, a flexible sleeve sealing the ring to the receptacle, and apneumatically permeable annular slot in the skin-engaging face of thesealing ring, passage means for subjecting the slot to suction forholding the proximate skin in sealing contact with the sealing ring, andadjustable positioning means interposed between the receptacle.

and the sealing ring for conforming the sealing ring to predeterminedfixed non-planar contour whereby the skin-engaging face of the sealingring may be conformed tothe body surface.

13. The combination of a receptacle constituting a treatment chambersubject to abatmospheric pressure and having an opening for exposing aportion of a body member to the treat-l ment chamber, a sealing ringhaving a skin-engaging face for application more or less atwise to thebody portion, a flexible sleeve sealing the ring to the receptacle, anda pneurnaticalljr permeable'annular slot in the skin-engaging face ofthe sealing ring, passage means for subjecting the slot to suction forholding the proximate skin in sealing contact with the sealing ring, a.fixed support, and ladjustable positioning means for the sealing ringfor conforming the sealing ring to predetermined fixed non-planarcontour whereby the skin-engaging face of the sealing ring may beconformed to the body surface, the adjustable positioning means beinginterposed between the sealing ring and the support whereby the saidproximate skin may be drawn away from the support upon which the bodyrests.

14. The combination of a receptacle 'constituting a treatment chambersubject to abatmospheric pressure and having an opening for exposing aportion of a body member to the treatment chamber, a sealing ring aroundthe opening sealed to the receptacle and having a lateral skin-engagingface directed more or less atwise against theannular area of skinbounding the portion exposedto the chamber through the opening, passagemeans subjecting the intermediate portion of the skin-engaging face tosuction for holding the skin in sealing engagement with the sealingring, and a support for the sealing ring independent of the body.

l5. Themethod of sealing a pneumatic treatment chamber to the skinbounding a body portion exposed to the chamber which consists insupporting a sealing ring independently of the body in -contouredposition conforming to the body area and sucking the proximate skin intosealing contact with thering by suction of a degree independent of thepressure in the treatment chamber. v

16. A sealing ring of the class described formed of resilient rubber andhaving a skin-engaging annular face, a rec-ess in the face', means forsubjecting the recess to suction, and a perforated metal wall extendingacross the recess and annularly conformed and-set back from theskinengaging face to constitute a skin support between the edges of therecess, -the edges of the metal wall being embedded in the rubber of thesealing ring.

17. A sealing ring ofthe classdescribed comprising -an annularskin-engaging face, an annular slot in the face defining spaced annular'sealing edges, an annular recess back of the skinto face the surface ofthe body of the patient,

means connected to the receptacle for periodically varying theabatmospheric pressure to which the exposed portion of the patients bodyis subjected, and means for-applying a continuous suction to the sealingring to cause the skin of the patient adjacent the margin of the openingin the receptacle to adhere over the open side of the sealing ring andthereby seal the receptacle tothe patient. 1

' 19. Therapeutic apparatus comprising a receptacle having an openingthrough which a portion of the body of a patient maybe exposed fersubjection to uid presslu'e treatment, a sealing ring framing theopening in the receptacle,

said sealing ring having an open side to face the surface of the body ofthe patient about the opening in the receptacle, means for periodicallyand alternately applying positive pressure and -suction'to thereceptacle to subject thereto the exposed portion of the patients body,and means lfor applying'a sustained suctionto the sealing ring to causethe skin of the patient adjacent the margin of the opening in thereceptacle to adhere over the open side of the sealing ringregardless ofthe variations of pressure condi-v tions within the receptacle.

SIMON BENSON.

